po 17. 2. 2020 v 19:23 odesílatel Tom Lane <tgl@sss.pgh.pa.us> napsal:
Pavel Stehule <pavel.stehule@gmail.com> writes: > po 17. 2. 2020 v 17:36 odesílatel Laurenz Albe <laurenz.albe@cybertec.at> > napsal: >> Either use shorter transactions, or start fewer subtransactions.
> it is interesting topic, but I don't see it in my example
> CREATE OR REPLACE FUNCTION public.fx(integer) > RETURNS void > LANGUAGE plpgsql > AS $function$ > begin > for i in 1..$1 loop > begin > --raise notice 'xx'; > exception when others then > raise notice 'yyy'; > end; > end loop; > end; > $function$
This example doesn't create or modify any table rows within the subtransactions, so (I think) we won't assign XIDs to them. It's consumption of subtransaction XIDs that causes the issue.
I tested
CREATE OR REPLACE FUNCTION public.fx(integer) RETURNS void LANGUAGE plpgsql AS $function$ begin for i in 1..$1 loop begin insert into foo values(i); exception when others then raise notice 'yyy'; end; end loop; end; $function$
and I don't see any significant difference between numbers less than 64 and higher
